兰州市安宁区桃畸果病病原鉴定和受害桃芽及果实显微组织观察

试验对兰州市安宁区桃畸果病害的发病原因和受害桃芽及果实组织结构变化进行了研究.结果表明:危害兰州市安宁区桃畸果病的病原为下心瘿螨(Eriophyes catacardiae Keifer);瘿螨对桃芽和果实均产生了很大影响,2010年桃芽受害率为52.9%,2011年为61.9%,严重时高达76%.受害桃芽干瘪瘦小,芽鳞片层数增加1~2层,严重的出现芽体坏死现象;对桃芽显微组织观察发现受害桃芽叶原基受损,严重的无叶原基,失去萌芽能力,在芽体鳞片内侧、苞片及幼叶间可见大量的寄生虫体取食为害;对果实形态及组织观察发现,受害果实表面出现不同程度深绿色凹陷,畸形部位桃毛密度和桃毛长度均高于正常果实;显微切片观察表明,受害果实细胞易于染色,细胞排列紧密,畸形果实细胞小于正常果实,畸形果实细胞直径为58μm,正常果实为102μm.     

基于LS-SVM的光伏最大功率跟踪控制方法

为解决自然环境剧烈变化条件下,传统光伏最大功率跟踪控制中存在的控制精度低和误跟踪现象,建立了基于最小二乘支持向量机的最大工作点电压预测模型,通过该模型预测光伏发电系统的最大工作点电压,并用预测电压来修正恒电压控制法的参考电压,从而实现光伏发电系统的最大功率跟踪控制。仿真结果表明预测模型具有较高的精度,相对误差在0.04以内,控制方法能够快速、稳定地实现光伏发电系统的最大功率跟踪,有效避免误跟踪现象。     

真鲷窒息点与耗氧率的初步测定

真鲷(Pagrosomus major T and S)是广东及其他各省市沿海海水网箱养殖的主要鱼类之一。随着真鲷人工繁殖和苗种培育的成功,真鲷养殖业将会有一个更大的发展。夫于鱼类的窒息点与耗氧率的研究早有不少,但是对真鲷除个别学者提及其窒息点外,真正对其窒息点与耗氧率的系统研究尚未见到。为了绘其鲷的人工繁殖、苗种培育、运输和成鱼养殖提供呼吸生理方面的理论依据,笔者于1990年春对真鲷的窒息点和耗氧率进行了初步测定,就不同规格大小的苗种及备种外界条件与窒息点和耗氧率之间的关系进行了初步探讨。     

Intercohort cannibalism and parturition-associated behaviour of adult swordtail, Xiphophorus helleri Heckel (Pisces: Poeciliidae)

The post‐parturition behavioural patterns of adult Xiphophorus helleri (Heckel) were described and quantified by recording their duration and/or frequency in glass tanks. All births occurred in the dark. Female behaviour might increase the chance of newborn juvenile survival: at the top of the tank, where juveniles are more vulnerable to predation, the females gave birth in the artificial refuge, while no parturition took place in the refuge at the bottom. Birth‐giving females were no less cannibalistic than males and other females. There was a reduction in cannibalism and the frequency of secondary attacks with time, even though the number of juveniles in the tank continued to increase due to ongoing parturition. Most adults were found at the bottom of the water column during the first 500 min of parturition, after which they were distributed equally in the water column. The movement of adults, away from the bottom and consequently away from the juveniles corresponded with an increase in feeding on alternative food and a reduction in cannibalism. Thus, cannibalism in swordtail might be opportunistic predation.     

湖南省生猪定点屠宰管理情况调研

为了解生猪定点屠宰管理的现状和存在问题,湖南省农业部门对长沙市、郴州市、衡阳市等地的屠宰管理情况进行了实地调查研究,并在此基础上提出了相应的对策和建议,为规范生猪定点屠宰管理提供了参考。     

大口黑鲈胰腺的组织学观察

采用组织切片和免疫组化技术对大口黑鲈的胰腺进行了组织学观察。经H-E染色和G-醛复红染色了的切片显示:大口黑鲈腹腔中10多个肉眼可见的黄白色颗粒物其实是被一层结缔组织和外分泌胰腺包裹着的胰岛结构,其中最大的一个即为主岛;还有许多肉眼不可见的胰岛结构被埋藏于总胆管的管壁中;肝脏中有外分泌胰腺的存在与分布。过氧化物酶标记的链霉卵白素免疫组化切片和图像分析显示:B细胞主要集中胰岛的中央区;A细胞分布于胰岛的全部。本研究的结论为:大口黑鲈的内分泌胰腺主要分布于总胆管周围,外分泌胰腺除了包裹于胰岛之外也分布于肝脏中,胰腺的分布属于弥散型。     

藏鸡的有丝分裂观察及染色体核型分析简

试验采用直接骨髓法制备林芝藏鸡染色体,通过显微自动成像系统观察藏鸡细胞有丝分裂全过程,包括间期、早前期、前期、中期、后期和末期,并分析了藏鸡有丝分裂过程染色体的形态变化规律。通过比较有丝分裂各期的形态,结果发现藏鸡有丝分裂的前期染色体伸展最长,碱基暴露最多,适合于做基因定位工作。同时进行了藏鸡染色体的核型分析,数据统计结果发现林芝地区藏鸡染色体数目2n=78,其中前5对染色体和性染色体中有3对中央着丝粒（m）染色体、1对近中着丝粒（sm）染色体、2对端着丝粒（t）染色体。与前人试验结果进行了比较,结果显示存在一定差异,原因仍需进一步试验验证。     

Fixed location hydroacoustic monitoring of fish populations in the tidal River Hull, north-east England, in relation to water quality

Abstract  Fixed location hydroacoustic fish monitoring was carried out at a series of sites in the tidal River Hull, north-east England, in July 1996 during periods of moderate freshwater flows and spring tides. This was followed by a corresponding series during a period of lower freshwater flows and spring tides in autumn 1996. The surveys indicated substantial numbers of fish living upstream and downstream of a depleted oxygen zone which exists in the tidal Hull. Conditions in this zone of poor water quality deteriorated further during low flow periods due to reduced dilution of effluents. Fish populations moved with the tide apparently in response to gradients of dissolved oxygen and salinity. Under conditions of low freshwater flow and high tides, gradients of salinity and oxygen were steeper and fish responses appeared more marked: at higher salinities, the response to increasing salinity overrode the response to decreasing oxygen availability.     

半滑舌鳎耗氧率和窒息点的初步研究

对半滑舌鳎的耗氧率和窒息点进行了初步研究。结果表明,在各个盐度梯度下,半滑舌鳎的耗氧量和耗氧率与体重(W)之间的关系可用幂函数Q=aWb表示,其中,耗氧量与体重呈正相关,耗氧率与体重呈负相关,方差分析表明,盐度和体重对半滑舌鳎的耗氧量和耗氧率均有极显著的影响(P<0 01);不同规格半滑舌鳎耗氧率的最高值均出现在同一盐度组,最低值则因体重不同而出现在不同的盐度组。半滑舌鳎的耗氧率无较明显的昼夜变化,夜里的耗氧率略大于白天,昼夜两阶段耗氧率的差异不显著。窒息点随着温度和体重的增加而有所增加,在较低的温度下,半滑舌鳎有很强的耐低氧能力。